Canning 101: How to Use Water Bath and Pressure Canners
Preserving the harvest is easier than you thought.
Canning 101: How to Use Water Bath and Pressure Canners
Preserving the harvest is easier than you thought.
Canning is a method to preserve food using boiling water or steam to create an airtight seal inside of a glass jar. It is a simple process that is often made out to be much more complicated than it actually is. That’s because it is often conflated with other aspects of food preservation, such as pickling vegetables or making fruit preserves. Canning is simply the final step in preserving these items – the complicated part is mastering all the ways that food can be processed before it is canned and put on the pantry shelf. There is tremendous variation in the recipes for foods that are canned and it is important to follow them precisely – especially when it comes to ingredients like pectin, sugar, citric acid, salt, and vinegar that play a role in preservation.
When it comes to canning technique, the main variable is which type of canning device will be used. Water bath canners – essentially a large pot with a metal rack on the bottom to support Mason jars – are suitable for fruits (which includes tomatoes). Here’s a version we like. Canning vegetables and animal products require a pressure canner (we recommend this version) to reach the temperature necessary to preserve these foods safely. Pressure canners cost a bit more than water bath canners, but are worthwhile given that botulism, a lethal disease associated with canned foods, can only be eliminated by temperatures above the boiling point of water in canned vegetables and animal products. (Note: The inherent acidity of fruits helps to prevent botulism, so there is no need for the extra heat in their case. Use a pressure canner for recipes where fruits and vegetables are mixed.)
[Canning] is a simple process that is often made out to be much more complicated than it actually is.
Other than that, the canning process varies only slightly with different types of foods, and this information will be included in the canning recipe. For both methods, you’ll need Mason jars (with lids and bands), a jar funnel, jar tongs, oven mitts, and a plastic spatula. The rubber gasket on Mason jar lids is the key component responsible for sealing out air and preventing spoilage – they are only designed to be used once, so pick up an extra pack of lids for each new round of canning. The threaded metal bands that hold the lids in place may be used over and over, however.
Water Bath Canning for Fruits
After the jars have cooled, confirm that they have been sealed by pressing into the lid with your finger. If the lid can be depressed and pops back up, it is not properly sealed. The lid should not move when pushed if the process was successful. You can also take off the bands and lift up the jars by the edge of the lid to test them – they should remain firmly in place. If the seal is not successful on any of the jars, repeat the canning process or just store them in the refrigerator for immediate consumption.
Pressure Canning for Vegetables and Animal Products
Pressure canners vary by manufacturer, but the process for using them is similar to water bath canning. The main difference is that the jars will sit in just a few inches of water, rather than being submerged. There is a vent on top of the canning pot that allows steam to escape, which needs to be left open for the first ten minutes of boiling (to allow the air to escape) and then closed (to keep the steam in).
For foods that need to be preserved with a pressure canner, the canning recipe should indicate the amount of time to leave the jars in the canner, as well as the amount of pressure that is necessary (in PSI, or pounds per square inch). Pressure canners are outfitted with pressure gauges and the heat can be raised or lowered to achieve the correct pressure level.
Check the instructions that come with the device for more details on how to operate it.
A Few Final Details
Elevation above sea level affects the boiling time needed to seal jars in a water bath canner and the pressure required for canning with a pressure canner. Recipes give the time and pressure for sea level, so use a conversion chart to find the appropriate numbers for the altitude where you live.
Successfully canned foods resist spoilage and retain their color, nutrients, and flavor for a year or more when stored in a cool dry place. It is important, however, to start with only the freshest ingredients – avoid using old, soft, diseased, or damaged produce. Always check the lids before using a canned product and discard any that are no longer sealed.
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Very good article steps for Water Bath Canning for Fruits is so useful. I would like to implement it.
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